Difference of Hammer Hanging Mechanisms on Standard Penetration Test Energy Transfer Ratio
Bibliographic record
Abstract
The Standard Penetration Test (SPT) has a long history of being used to estimate geotechnical soil parameters. The basis of the test relies on impacting a drill rod string with a hammer to advance a sampler, where the SPT N index is the number of hammer blows required to advance the sampler to a known distance. To reduce the variability of SPT N values between tests, several correction factors have been proposed to control for differences, including a correction for the energy transfer imparted from the hammer. A variant of the SPT, the Large Penetration Test (LPT), is sometimes used when gravels are anticipated, which may interfere with the penetration of the sampler in the SPT. The LPT test is conducted similarly to the SPT but uses a larger hammer and sampler. Within British Columbia, contractors typically use hydraulic automatic trip hammers from different manufacturers for both penetration tests. However, depending on the drill rig, the hammer may be affixed by a frame system to the drill mast or held by a winch line. This paper presents a case history where two nearby sites conducted instrumented SPTs and LPTs to obtain site-specific energy transfer ratios. At one site, the SPTs were conducted with the hammer affixed to the drill mast through a frame system; the other site conducted instrumented SPTs and LPTs with the hammer held up by a winch line system. The paper compares the inter-test and intra-test Energy Transfer Ratio (ETR) differences between the hammer suspension systems. Significant differences in ETR were observed between the two different hammer suspension systems. The average ETR within the test intervals varied from 79.4% to 93.9% in the SPTs and from 77.6% to 96.0% in the LPTs for different tests conducted with the hammer was suspended by the winch line. For the SPT tests conducted with the hammer affixed to the drill mast, the correlated ETR varied between 86.8% and 89.8% over the test intervals.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.021 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".